This relates to imaging systems and, more particularly, to image sensors with antireflective layers.
Digital cameras are often provided with digital image sensors such as CMOS (complementary metal-oxide-semiconductor) image sensors. Digital cameras may be stand-alone devices or may be included in electronic devices such as cellular telephones or computers. A typical CMOS image sensor has an array of image sensing pixels containing contain thousands or millions of pixels. Lenses focus incoming light onto the array of pixels. Layers such as a dielectric stack, a passivation layer, and a color filter layer may be located between the lenses and the image sensing pixels. Metal interconnects and vias are formed in the metal and dielectric layers of the dielectric stack. The passivation layer can be formed above the dielectric stack. The color filter layer contains filters for filtering light of different colors.
Image sensor performance is influenced by the efficiency with which image sensor pixels gather incoming light. In conventional image sensors, some of the incoming light is reflected away from the pixels at the interface between the color filter array and the passivation layer and at the interface between the passivation layer and the dielectric stack, thereby reducing the performance of the image sensors.
It would therefore be desirable to provide improved image sensors with increased efficiency of gathering incoming light.